1. Field of the Invention
The present invention relates to a cord safety device for a window covering, and more particularly to a cord safety device, in which once one of the pull cords is moved to a predetermined position of the cord safety device, an angled opening of the cord safety device is opened sidewardly and the cord safety device is further divided into two bodies completely, such that the cords and the bodies are quickly released, thereby preventing the cords from forming a closed loop and a child from strangling when the child's neck caught in the loop.
2. Related Art
Currently, common cord lock structures for window coverings are mostly hollow-shaped and have a through hole in the center of an end surface thereof. Meanwhile, (a plurality of) cords of the window coverings pass through the said through hole. Then, the tail end of each cord is respectively knotted, or the tail ends of all the cords are tied into one big knot, so as to limit the tail ends of the cords by the through hole, wherein the cords and the cord lock are combined. However, the knots at the tail ends of the cords or the combination of the cords and the cord lock are easily formed into a closed cord loop. Once a child plays under the cords or uses the cords inappropriately, he/she may be caught by the closed cord loop and may not get rid of the cord loop independently, and as a result, an accidental strangling may occur. In order to solve the above problem, relevant patents have been disclosed, which are described as follows.
The U.S. Pat. No. 5,473,797 (Prior Art 1) discloses a safety device for fixing cords of Venetian blind. When placing the cords in the safety device, it does not need to knot at the tail ends of the cords, but directly puts the cords into a space between an inner surface of a fending edge and an elastic stop blade, thereby clipping the cords. In case of operating the blinds in an inappropriate way, since an external force is larger than the clipping force, the cords are forced to be opened and separated from each other. In this manner, the assembled upper and lower covers are apart from each other, and the cords are quickly separated and released accordingly. However, if the external force is not larger than the clipping force of the cord buckle, the assembly may possibly not release the cords as designed.
The U.S. Pat. No. 5,504,977 (Prior Art 2) discloses a device for releasably holding cords, in which one of the bodies includes an inclined guiding surface and a slot located on the bottom part. One of the cords is fastened on one side of the body, and the other cord is guided along the inclined guiding surface. When the cords are exerted with an external force, the knots of the cords slide towards the slot at the bottom part along the inclined guiding surface, such that the cords are separated from the body. However, when the cords are in the tightened state and cannot be guided downwards along the inclined guiding surface to reach the slot at the bottom part, the device may possibly not release the cords as designed.
The U.S. Pat. No. 5,560,414 (Prior Art 3) discloses a releasable operating cord connector for a window covering, in which the cord connector has at least two bodies, and the knots of the cords are stopped by the cord stops of the two said bodies that are moved relative to each other. Furthermore, the relative edges of the two bodies have a combining portion respectively to combine each other and form the cord connector. When the neck of the child or the user is caught by accident while he/she is playing with the cords, the tensioned operating cords apply forces against the combining portions to urge the bodies into an open condition, such that the cords are quickly loosened and released from the bodies completely, so as to avoid an accidental strangling. However, when the applied external force is not sufficient for urging the combining portions into an open condition, it may possibly fail the function of separating the cords from the bodies.
The U.S. Pat. No. 5,562,140 (Prior Art 4) discloses a releasable operating cord connector for window covering, which has a fixed side member and a movable side member pivoted on the fixed side member. The two side members respectively have a cord abutment means and a cord retaining means. When the cord abutment means are combined, an opening for the cords to pass is formed on the upper part thereof, and each cord retaining means limits the knots of the cords. In case of an abnormal usage, the cords are urged into an open condition due to the external force, so as to open the combined cord abutment means and the cord retaining means, and thus, the cords are quickly separated from the side members. However, when the external force is not sufficient for opening the cord abutment means, it may possibly lose the function of separating the cords from the side members.
The U.S. Pat. No. 5,592,983 (Prior Art 5) discloses a pull cord safety device, which is similar to the structure of the Prior Art 4, except that in the Prior Art 4, the knots of the cords are stopped by the cord retaining means, whereas in this patent (Prior Art 5), the knots of the cords are stopped by an opening of the members, and the functions thereof are the same as that in the Prior Art 4, which thus will not be described repeatedly. However, when the external force is not large enough to open the opening, it may possibly lose the function of separating the cords from the members.
The U.S. Pat. No. 5,906,233 (Prior Art 6) discloses a safety device and system for window covering pull cords, in which two cords are respectively disposed on left and right members, and each member has a relatively inclining surface engaged with a snapping portion as a whole. Once an external force is applied to the two cords, if the distance of the two pull cords is larger than a parallel engaging distance between the inclined surface structures for the members, the snapping portions in the members are separated from each other, so as to separate the two members and to release the cords accordingly. However, if it intends to dispose a plurality of cords, a plurality of devices is required to combine the cords into different layers, which results in the complicity and inconvenience for assembling and disassembling the cords.
The U.S. Pat. No. 6,910,517 (Prior Art 7) discloses an equalizing connector for multi-cord architectural covering, in which the connector structure includes two releasable outer shells and a compressible inner assembly. Due to an upward spring force generated by the inner assembly, the upper end position of the outer shell is snapped, and the two cords are respectively fixed in recesses on two sides of each outer shell. When the cords are forced to open due to the external force, the combined outer shells are pulled and separated from each other, such that the outer shells are inversely separated towards two opposite sides to form two separate components. However, if the elastic force generated by the inner assembly is weakened, it will not catch the two sides of the outer shell. Furthermore, if it intends to dispose a plurality of cords, a plurality of buckles is required for combining those cords, which results in the complexity and inconvenience for assembling and disassembling the cords.
However, in the above cord safety devices, the open end is located on the upper part, such that it needs to apply forces to separate the cords from the side members. If the force applied to the cords is not sufficient for opening the cord safety device, or the included angle or distance between the cords is not large enough for opening the cord safety device, it cannot separate the cords from the side members to release the cords easily, which may result in accidents. If more than two cords are mounted, a plurality of buckles is required for combining those cords, which results in the assembling and disassembling difficulties. Therefore, such devices still have defects in usage, and it is necessary to make improvements on such cord safety device, so as to offer safety and convenience to the user.